1. Field of the Invention
This invention relates to an apparatus which is added to an image formation apparatus such as a copying apparatus, a printer or a recording machine and which handles paper leaves such as originals, copy paper or recording paper.
2. Description of the Prior Art
As a part of a copying apparatus, a sorter has heretofore been integrally attached to the copying apparatus to distribute and receive paper leaves such as copy paper having images formed thereon (hereinafter referred to as sheets), but along with the growing tendency toward automatization and manpower saving, it is now also used with a small apparatus or a popular apparatus. Also, a copying apparatus now has optional components and thus it has come to be separated into a copying apparatus body and a sorter. Thus, various members for the connection of the copying apparatus and the sorter have been devised and various contrivances have been made so that their operability may not be marred. However, none of the various methods heretofore devised enables the operator to know whether the copying apparatus and the sorter have been properly connected together, and it has often been the case that the operator commits errors or the copying apparatus fails to run and thereby makes the operator disoriented.
Generally, a sorter has a sheet receiving bed (a tray group) comprising ten to twenty or more stages and sheets continuously carried out from an apparatus such as a copying apparatus at predetermined intervals are successively conveyed and received into a predetermined tray by belt conveyor means, a plurality of roller means or conveyor means comprising a combination of these.
Among sorters, there is one in which the trays disposed at the carry-out port of an apparatus such as a copying apparatus are successively moved when distribution and reception of sheets are effected.
In such a sorter, the tray group is maintained stationary at a certain position by fall preventing means such as a pawl. Accordingly, when the tray group is to be moved downwardly from a certain position, the tray group must be once moved upwardly and the pawl must be released, whereafter the tray group must be moved downwardly. This has heretofore been accomplished by changing over a motor to move the tray group upwardly for a predetermined timer time and move it downwardly after the timer time. However, the amount of movement of the tray group within the timer time is irregular over a wide range due to the influences of the quantity of sheets in the tray group, the irregularity of the speed of the motor, the mechanical back-lash of the tray group moving mechanism, etc. Therefore, such a situation that the motor is changed over in spite of the pawl having not completely been released may occur and, when such a situation occurs, damage of the pawl, damage of the power transmitting mechanism from the motor shaft, etc., occur and this is very dangerous.
In such a sorter, the tray group is moved upwardly or downwardly even when copying on only one sheet is effected, and if the copying apparatus and the sorter are controlled in a dialog form, there occurs a waste of time and a repeated upward and downward movement of the tray group which leads to a disadvantage in mechanical durability.
Also, where such a sorter is connected and used with a copying apparatus which permits interruption copying, if interruption copying is carried out during sorting, the tray into which the sheet for the interruption copying has been received cannot be identified. Thus, there occurs an inconvenience that interruption copying cannot be carried out during sorting.
Also, in such a sorter, as a method of detecting the position of each tray, three microswitches, for example, have been used to detect the uppermost position, the lowermost position and the intermediate position, respectively. Such method, however, requires three detecting members which means a higher cost. Also, the entrance of each tray must generally be designed with strict dimensions inasmuch as a number of sheets must be piled on each tray, and it is necessary to stop the tray group with high accuracy so that sheets may be accurately carried into each tray through the entrance. In the case of microswitches, this accuracy all depends on the operating point of the microswitches. As is well known, however, the operating point of microswitches is greatly irregular and has a hysteresis characteristic and moreover, microswitches are poor in durability and are very unsuitable for an apparatus which requires reciprocal movement. Where three photointerrupters are employed in place of microswitches, it is necessary to provide three tray position indicating members opposed to these photointerrupters, and this leads to a very complicated construction as well as a disadvantage in terms of the space required.
Also, in a copying apparatus or the like, together with a sorter, an automatic sheet original feeding device is sometimes used to feed sheet originals one by one to the original supporting surface of the copying apparatus. Such automatic sheet original feeding device is grouped into two types, namely, the type in which a number of sheet originals are placed on a feeding tray at a time and fed therefrom one by one and the type in which sheet originals are placed one by one on the feeding tray and fed therefrom.
In the device of the latter type, the handling of the original is effected by the copy start button of the copying apparatus or an original insertion button provided on the automatic original feeding device, after the original has been inserted. In any case, however, the start button must be depressed after the original has been inserted. That is, the procedures of inserting each original and depressing the button after each original has been inserted are required and this is very cumbersome.